Electronic imaging or scanning systems are commonly used to transform an image or an image-bearing surface from one form, such as a paper original, to an electronic form, such as a digital or analog signal. Once an image is converted to electronic form, many uses of that signal become possible, including, without limitation, the reproduction of the image onto a piece of paper, the projection of the image onto a video display terminal, the transmission of the image to a remote location, and the further processing of that image, such as by a computer, an optical pattern recognition device, or the like.
Electronic imaging systems typically include an array of photosensitive elements, such as photosensors, and a light source operatively disposed to provide illumination of the surface being scanned. In those instances where a linear array of photoresponsive elements is employed, it is necessary that either the image on that surface is moved in a direction perpendicular to the longitudinal axis of the linear array, or the linear array of photoresponsive elements is moved in a direction perpendicular to the longitudinal axis of that surface. Alternatively, in those instances where a two dimensional array of photoresponsive elements is employed, the entirety of the document may be scanned without the need for relative motion therebetween. Regardless of whether linear or two dimensional arrays are employed, the light reflected from the image-bearing surface varies depending upon the image on any small area portion of the surface being scanned, i.e., a darker portion of the surface will cause the photosensitive elements to receive less reflected light, while a brighter portion of the surface will cause the photosensitive elements to receive more reflected light. Since the photosensitive elements effect a detectable change in the electrical conductivity thereof in response to the receipt of differing amounts of incident radiation, the change in conductivity can be detected and relayed in the form of electrical signals.
It will be appreciated that electronic image scanning systems are of great commercial utility insofar as they permit the conversion of human readable data into electronic format, which format is compatible with various electronic processing, transmission and storage operations. Accordingly, electronic image scanners have gained acceptance in such diverse fields as publishing, finance, engineering, telecommunications and the graphic arts. Since electronic image scanners are essentially the "eyes" of data processing systems, their ubiquity should be as great as that of the desk-top computer terminal; however, such is not the case at present point in time owing, in part to the expense, size and limited scanning capacity of heretofore available scanners.
The assignee of the subject invention has already developed large area electronic image scanners which are specifically adapted to reproducibly scan a pattern of information on a drafting table or a marker board and produce a digital signal corresponding thereto. Such large area scanners are disclosed in commonly assigned U.S. patent application No. 885,907 filed July 15, 1986 and entitled "Photosensitive Line Imager Utilizing A Movable Scanning Arm, now U.S. Pat. No. 4,725,889, the disclosure of which is incorporated herein by reference. Applicants are also aware of various other commercially available image scanners; however, all of such scanners are relatively large, complex and expensive systems. Therefore, the need remain for a small size electronic image scanner, suitable for portable as well as desk-top use. Such a scanner should be relatively simple to operate and fairly inexpensive so as to be readily available as an adjunct to personal computing systems and the like. Furthermore, it is highly desirable that any such an electrical image scanner be capable of scanning irregularly shaped or oversized documents such as bound material, newspapers, magazines, plywood, textiles and the like.
The aforementioned industrial needs are fulfilled by the portable and desk-top digitizer disclosed herein. More specifically, the instant invention provides for a compact, low cost electrical image scanner capable of providing a digital signal corresponding to information upon a wide variety of substrates including, single printed pages, bound materials, oversized documents and drawings or the surface condition present on woods, metals, plastics and textiles. The scanner of the present invention includes a digitizing wand, said wand equipped with a photosensor array therein. Manual scanning of the variety of documents, or other information-bearing surfaces, may be readily accomplished by merely passing the wand across the information-bearing surface so as to allow the photosensor array to scan that surface. The scanner of the instant invention further includes a base station configured for placement on a horizontal surface such as a desk or mounting on vertical surface such as a wall. The base station is adapted to removably and operatively retain the scanning wand when the wand is not in portable use. The base station may further be provided with the capability of receiving a document to be scanned and establishing relative motion between that document and the scanning wand. Such relative motion may be achieved by either moving the document past the stationary wand or by moving the wand past the stationary document. In this manner, th image scanner of the instant invention is adapted for the automatic scanning of image-bearing documents in a manner akin to the more conventional scanners referred to hereinabove.
It may thus be seen that the present invention discloses a unique electronic image scanner which is of relatively small size so as to enable said scanner to be disposed upon desks or other work surfaces. The image scanner of the instant invention includes a demountable scanning wand which may be used in a portable manner so as to manually scan bound or odd-size documents. The image scanne of the instant invention is further adapted to automatically scan an image-bearing document placed into the base station thereof. Because of its small size and high degree of flexibility, the image scanner of the instant invention provides a high degree of utility and answers a long felt need in the industrial marketplace.
These and other features and advantages of the present invention will be apparent from the drawings, the brief description of the drawings and the detailed description of the drawings which follow.